Venus 2000

From Opendildonics.org

A power unit consists of a gearmotor which drives a reciprocating diaphragm. Air moves in and out through a hose connected to a hard plastic sleeve lined with flexible rubber. The change in air volume alternately constricts and relaxes the liner while a one-way valve at the closed end of the liner ensures the user's penis is drawn in on negative pressure.

Details and interior pictures at

• http://www.libchrist.com/sybianvenus/Optimization/index.html